How a car suspension works Part-1

When people think of automobile performance, they normally think of horsepower,torque and zero-to-60 acceleration. But all of the power generated by a pistonengine is useless if the driver can't control the car. That's why automobileengineers turned their attention to the suspension system almost as soon asthey had mastered the four-stroke internal combustion engine.

The job of a car suspension is to maximize the friction between the tires and the roadsurface, to provide steering stability with good handling and to ensure thecomfort of the passengers. In this article, we'll explore how car suspensionswork, how they've evolved over the years and where the design of suspensions isheaded in the future.

If a road were perfectly flat, with no irregularities, suspensions wouldn't benecessary. But roads are far from flat. Even freshly paved highways have subtleimperfections that can interact with the wheels- of a car. It's theseimperfections that apply forces to the wheels. According to Newton's laws ofmotion, all forces have both magnitudeand direction. A bump in the road causes the wheel to move up and down perpendicular to theroad surface. The magnitude, of course, depends on whether the wheel isstriking a giant bump or a tiny speck. Either way, the car wheel experiences a vertical accelerationas it passes over an imperfection.

Without an intervening structure, all of wheel's vertical energy is transferredto the frame, which moves in the same direction. In such a situation, thewheels can lose contact with the road completely. Then, under the downwardforce of gravity, the wheels can slam back into the road surface. What you need is a system thatwill absorb the energy of the vertically accelerated wheel, allowing the frameand body to ride undisturbed while the wheels follow bumps in the road.

The study of the forces at work on a moving car is called vehicle dynamics,and you need to understand some of these concepts in order to appreciate why asuspension is necessary in the first place. Most automobile engineers considerthe dynamics of a moving car from two perspectives:

Ride - a car's ability to smooth out a bumpy road

Handling - a car's ability to safely accelerate, brake and corner

These two characteristics can be further described in three important principles - road isolation, road holding and cornering. The tablebelow describes these principles and how engineers attempt to solve thechallenges unique to each.

A car's suspension, with its various components, provides all of the solutionsdescribed.